WO2017090135A1

WO2017090135A1 - Pneumatic tire

Info

Publication number: WO2017090135A1
Application number: PCT/JP2015/083120
Authority: WO
Inventors: 畑　寛; 松田　淳; 基云金; 昶重朴
Original assignee: 横浜ゴム株式会社; クムホタイヤカンパニーインコーポレーテッド
Priority date: 2015-11-25
Filing date: 2015-11-25
Publication date: 2017-06-01
Also published as: CN108349332A; US20180345730A1; KR20180064524A; DE112015007152T5; JPWO2017090135A1

Abstract

In order to ensure outside noise reduction, this pneumatic tire comprises a lug groove (24) that opens outwards in the tire width direction on the outermost side of the tread (2) in the tire width direction, and is provided with a projection (10) which is disposed outside of the opening of the lug groove (24) in the tire width direction, and which, in a state assembled on a normal rim, filled with normal internal pressure and loaded with 70% of the normal load, extends outwards in the tire radial direction beyond the bottom (R) of the lug groove (24) at maximum groove depth, and the leading end (10a) of the projection (10) is arranged inwards of the tread surface (S) of the tread (2) in the tire radial direction. On at least the base end (10b) of the projection (10), a reinforcing part (11) is provided that has a JIS-A rubber hardness higher than that of the surrounding rubber material.

Description

Pneumatic tire

The present invention relates to a pneumatic tire that reduces noise outside the vehicle.

Conventionally, pneumatic tires for the purpose of reducing outside noise have been proposed. For example, the pneumatic tire described in Patent Document 1 has a lug groove that opens to the outer side in the tire width direction on the outermost side in the tire width direction of the tread portion, and a protruding portion on the outer side in the tire width direction from the opening of the lug groove. It has. According to this pneumatic tire, the protrusion is located at the position of the opening on the outer side in the tire width direction of the lug groove, so that when the vehicle equipped with the pneumatic tire is traveling, the air from the lug groove to the outer side in the tire width direction is reduced. Prevents the emission of column resonance sound. As a result, noise outside the vehicle can be reduced.

Further, for example, the pneumatic tire described in Patent Document 2 includes, on the outer surface of the buttress portion, a protrusion that protrudes outward in the tire radial direction and continuously extends in the tire circumferential direction.

Also, for example, the pneumatic tire described in Patent Document 3 includes a protrusion for reducing water splash on the side wall. The protrusion is provided with a soft rubber layer having a JIS-A rubber hardness of less than 55 degrees and smaller than the tread rubber.

JP 2012-096776 A JP 2012-006483 A JP 2012-066662 A

In Patent Document 1 and Patent Document 2 as described above, the protrusions block sound emission to the outside in the tire width direction. However, since the protrusion deforms along with the deformation at the time of ground contact due to the rolling of the pneumatic tire, it becomes a vibration source itself and generates noise outside the vehicle. The reduction effect may not be obtained.

The present invention has been made in view of the above, and an object thereof is to provide a pneumatic tire capable of ensuring the effect of reducing outside noise.

In order to solve the above-described problems and achieve the object, the pneumatic tire of the present invention has a lug groove that opens to the outer side in the tire width direction on the outermost side in the tire width direction of the tread portion, and the opening portion of the lug groove More tires than the groove bottom of the maximum groove depth of the lug groove in the meridional section with the rim assembled on the normal rim, filled with the normal internal pressure, and loaded with 70% of the normal load. In a pneumatic tire including a protruding portion that extends radially outward and has a tip disposed on the inner side in the tire radial direction than the tread surface of the tread portion, at least at the base end of the protruding portion from a surrounding rubber material And a reinforcing part having a high JIS-A rubber hardness.

According to this pneumatic tire, at least the base end of the protrusion is provided with the reinforcing portion having a JIS-A rubber hardness higher than that of the surrounding rubber material, so that deformation of the protrusion is suppressed. As a result, the generation of noise due to the vibration of the protrusion can be suppressed, and the original sound shielding effect of the protrusion can be obtained, so that the effect of reducing outside noise can be ensured.

Further, in the pneumatic tire of the present invention, the reinforcing portion is characterized in that a height h is 60% or more and 100% or less with respect to an extending height H of the protruding portion in the meridional section.

According to this pneumatic tire, the height h of the reinforcing portion is in the range of 60% or more and 100% or less with respect to the extending height H of the protruding portion, thereby suppressing the deformation of the protruding portion and the deformation of the protruding portion. The effect which suppresses the vibration by can be acquired notably. When the height h of the reinforcing portion is less than 60% with respect to the extending height H of the protruding portion, the effect of suppressing the deformation of the protruding portion is reduced.

Further, in the pneumatic tire of the present invention, the reinforcing portion is characterized in that a thickness t is 50% or more and 100% or less with respect to a thickness T of the protrusion in the meridional section.

According to this pneumatic tire, the thickness t of the reinforcing portion is in the range of 50% or more and 100% or less with respect to the thickness T of the protruding portion, thereby suppressing the deformation of the protruding portion and vibration due to the deformation of the protruding portion. The effect which suppresses can be acquired notably. When the thickness t of the reinforcing portion is less than 50% with respect to the thickness T of the protrusion, the effect of suppressing the deformation of the protrusion is reduced.

In the pneumatic tire of the present invention, the reinforcing portion has a JIS-A rubber hardness that is 3 pt or more higher than the highest JIS-A rubber hardness of the rubber material around the protrusion.

According to this pneumatic tire, the JIS-A rubber hardness of the reinforcing portion is made 3 pt higher than the highest JIS-A rubber hardness of the rubber material around the protruding portion, thereby suppressing the deformation of the protruding portion. The effect which suppresses the vibration by deformation | transformation of can be acquired notably.

Further, in the pneumatic tire of the present invention, the protrusion is characterized in that irregularities are formed on the inner surface in the tire width direction.

According to this pneumatic tire, the unevenness is formed on the inner surface of the protrusion in the tire width direction, so that the surface area of the inner surface of the protrusion in the tire width direction is increased, thereby blocking air column resonance noise. Since the area increases, the sound shielding effect can be obtained remarkably.

Further, in the pneumatic tire of the present invention, the protrusion is assembled with a normal rim, filled with a normal internal pressure, and loaded with 70% of the normal load. The distance in the tire radial direction is 0.5 mm or more.

If the distance in the tire radial direction between the tread surface and the tip is less than 0.5 mm, when the pneumatic tire is deformed while the vehicle is running, the frequency of the protrusions coming into contact with the road surface increases and the protrusions are deformed. There is a tendency to do a lot. Therefore, according to this pneumatic tire, by setting the distance in the tire radial direction between the tread surface and the tip in the tire radial direction to be 0.5 mm or more, a situation in which the protrusion is deformed is reduced. Can be secured.

Further, in the pneumatic tire according to the present invention, the protrusion is assembled with a normal rim, filled with a normal internal pressure, and loaded with 70% of the normal load. Is an angle of 15 ° or less on the inner side in the tire width direction and 45 ° or less on the outer side in the tire width direction.

When the angle formed by the center straight line and the tire radial direction line exceeds 15 ° inward in the tire width direction, the protrusions easily come into contact with the tire body, and there is a possibility of causing wear or chipping at the contacted portion. On the other hand, if the angle formed by the center straight line and the tire radial direction line exceeds 45 ° on the outer side in the tire width direction, the projection part moves away from the lug groove, making it difficult to obtain a sound shielding effect. Therefore, according to this pneumatic tire, the angle formed by the center straight line and the tire radial direction line is 15 ° or less on the inner side in the tire width direction and 45 ° or less on the outer side in the tire width direction. When the outside is positive, the sound shielding effect by the protrusions can be remarkably obtained by setting the range of −15 ° to + 45 °.

Further, in the pneumatic tire of the present invention, the direction inside and outside the vehicle is specified when the vehicle is mounted, and the protrusion is formed at least on the vehicle outer side.

Since the noise outside the vehicle is emitted to the outside of the vehicle, according to this pneumatic tire, the projection can be formed at least on the outside of the vehicle so that the sound can be effectively shielded and the noise outside the vehicle is reduced. be able to.

The pneumatic tire according to the present invention can ensure the effect of reducing outside noise.

FIG. 1 is a meridional sectional view of a pneumatic tire according to an embodiment of the present invention. FIG. 2 is a meridional sectional view of the pneumatic tire according to the embodiment of the present invention. FIG. 3 is an enlarged view of a main part of the pneumatic tire shown in FIGS. 1 and 2. FIG. 4 is an enlarged view of a main part of the pneumatic tire shown in FIGS. 1 and 2. FIG. 5 is a side view of the protrusion viewed from the inside in the tire width direction. FIG. 6 is a side view of the protrusion viewed from the inside in the tire width direction. FIG. 7 is a side view of the protrusion viewed from the inside in the tire width direction. FIG. 8 is a side view of the protrusion as viewed from the inside in the tire width direction. FIG. 9 is a side view of the protrusion viewed from the inside in the tire width direction. FIG. 10 is an enlarged cross-sectional view of a main part of another example of the pneumatic tire according to the embodiment of the present invention. FIG. 11 is a partial perspective view of another example of the pneumatic tire shown in FIG. FIG. 12 is a chart showing the results of the performance test of the pneumatic tire according to the example of the present invention. FIG. 13 is a chart showing the results of the performance test of the pneumatic tire according to the example of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by this embodiment. The constituent elements of this embodiment include those that can be easily replaced by those skilled in the art or those that are substantially the same. Further, a plurality of modifications described in this embodiment can be arbitrarily combined within the scope obvious to those skilled in the art.

1 and 2 are meridional sectional views of a pneumatic tire according to the present embodiment.

In the following description, the tire radial direction refers to a direction orthogonal to the rotation axis (not shown) of the pneumatic tire 1, and the tire radial direction inner side refers to the side toward the rotation axis in the tire radial direction, the tire radial direction outer side. Means the side away from the rotation axis in the tire radial direction. Further, the tire circumferential direction refers to a direction around the rotation axis as a central axis. Further, the tire width direction means a direction parallel to the rotation axis, the inner side in the tire width direction means the side toward the tire equator plane (tire equator line) CL in the tire width direction, and the outer side in the tire width direction means the tire width direction. Is the side away from the tire equatorial plane CL. The tire equatorial plane CL is a plane that is orthogonal to the rotation axis of the pneumatic tire 1 and passes through the center of the tire width of the pneumatic tire 1. The tire width is the width in the tire width direction between the portions located outside in the tire width direction, that is, the distance between the portions farthest from the tire equatorial plane CL in the tire width direction. The tire equator line is a line along the tire circumferential direction of the pneumatic tire 1 on the tire equator plane CL. In the present embodiment, the same sign “CL” as that of the tire equator plane is attached to the tire equator line. In addition, since the pneumatic tire 1 described below is configured to be substantially symmetric with respect to the tire equatorial plane CL, in the meridional sectional view (FIGS. 1 and 2), the tire equatorial plane CL is Only one central side (left side in FIGS. 1 and 2) is illustrated and only the one side is described, and description of the other side (right side in FIGS. 1 and 2) is omitted.

As shown in FIGS. 1 and 2, the pneumatic tire 1 of the present embodiment includes a tread portion 2, shoulder portions 3 on both sides thereof, a sidewall portion 4 and a bead portion 5 that are successively continuous from the shoulder portions 3. have. The pneumatic tire 1 includes a carcass layer 6, a belt layer 7, a belt reinforcing layer 8, and an inner liner layer 9.

The tread portion 2 is made of a tread rubber 2 A, exposed at the outermost side in the tire radial direction of the pneumatic tire 1, and the surface thereof is the contour of the pneumatic tire 1. A tread surface 21 is formed on the outer peripheral surface of the tread portion 2, that is, on the tread surface that contacts the road surface during traveling. The tread surface 21 is provided with a plurality of (four in this embodiment) main grooves 22 which are straight main grooves extending along the tire circumferential direction and parallel to the tire equator line CL. The tread surface 21 is formed with a plurality of rib-like land portions 23 extending along the tire circumferential direction by the plurality of main grooves 22. The main groove 22 may be formed to be bent or curved while extending along the tire circumferential direction. The tread surface 21 is provided with a lug groove 24 extending in a direction intersecting the main groove 22 in the land portion 23. In the present embodiment, the lug groove 24 is shown in the outermost land portion 23 in the tire width direction. The lug groove 24 may intersect the main groove 22, or at least one end of the lug groove 24 may not terminate the main groove 22 and terminate in the land portion 23. When both ends of the lug groove 24 intersect with the main groove 22, a block-shaped land portion in which the land portion 23 is divided into a plurality of portions in the tire circumferential direction is formed. Note that the lug groove 24 may be formed to be bent or curved while extending while being inclined with respect to the tire circumferential direction.

The shoulder portion 3 is a portion of the tread portion 2 on both outer sides in the tire width direction. That is, the shoulder portion 3 is made of the tread rubber 2A. Further, the sidewall portion 4 is exposed at the outermost side in the tire width direction of the pneumatic tire 1. The sidewall portion 4 is made of a side rubber 4A. As shown in FIG. 1, the side rubber 4A has an end portion on the outer side in the tire radial direction disposed on the inner side in the tire radial direction of the end portion of the tread rubber 2A, and an end portion on the inner side in the tire radial direction is a rim cushion rubber 5A described later. It is arrange | positioned at the tire width direction outer side of the edge part. As shown in FIG. 2, the side rubber 4A may have an end portion on the outer side in the tire radial direction arranged outside the end portion of the tread rubber 2A in the tire radial direction. The bead unit 5 includes a bead core 51 and a bead filler 52. The bead core 51 is formed by winding a bead wire, which is a steel wire, in a ring shape. The bead filler 52 is a rubber material disposed in a space formed by folding the end portion in the tire width direction of the carcass layer 6 at the position of the bead core 51. The bead portion 5 has a rim cushion rubber 5A exposed at an outer portion that contacts a rim (not shown). The rim cushion rubber 5A is provided from the tire inner side of the bead part 5 to the position (side wall part 4) that covers the bead filler 52 on the tire outer side through the lower end part.

The carcass layer 6 is configured such that each tire width direction end portion is folded back from the tire width direction inner side to the tire width direction outer side by a pair of bead cores 51 and is wound around in a toroidal shape in the tire circumferential direction. It is. The carcass layer 6 has a configuration that is mainly continuous in the radial direction. However, the carcass layer 6 may have a dividing portion on the inner side in the tire radial direction of the tread portion 2. The carcass layer 6 is formed by coating a plurality of carcass cords (not shown) arranged in parallel at an angle in the tire circumferential direction with an angle with respect to the tire circumferential direction being along the tire meridian direction. The carcass layer 6 is provided as at least one layer.

The belt layer 7 has a multilayer structure in which at least two

belts

71 and 72 are laminated, and is disposed on the outer side in the tire radial direction which is the outer periphery of the carcass layer 6 in the tread portion 2 and covers the carcass layer 6 in the tire circumferential direction It is. The

belts

71 and 72 are formed by coating a plurality of cords (not shown) arranged in parallel at a predetermined angle (for example, 20 degrees to 30 degrees) with a coat rubber with respect to the tire circumferential direction. Further, the overlapping

belts

71 and 72 are arranged so that the cords intersect each other.

The belt reinforcement layer 8 is provided as necessary for reinforcement. The belt reinforcing layer 8 is disposed on the outer side in the tire radial direction which is the outer periphery of the belt layer 7 and covers the belt layer 7 in the tire circumferential direction. The belt reinforcing layer 8 is formed by coating a plurality of cords (not shown) arranged substantially parallel (± 5 degrees) in the tire circumferential direction and in the tire width direction with a coat rubber. The belt reinforcing layer 8 shown in FIG. 1 and FIG. 2 is disposed so as to cover the entire belt layer 7 and laminated so as to cover the end portion of the belt layer 7 in the tire width direction. The configuration of the belt reinforcing layer 8 is not limited to the above, and is not clearly shown in the figure. For example, the belt reinforcing layer 8 is arranged so as to cover the entire belt layer 7 with two layers, or only the end in the tire width direction of the belt layer 7. You may arrange | position so that it may cover. Further, although the configuration of the belt reinforcing layer 8 is not clearly shown in the drawing, for example, it is arranged so as to cover the entire belt layer 7 with one layer, or to cover only the end of the belt layer 7 in the tire width direction. It may be arranged. That is, the belt reinforcing layer 8 overlaps at least the end portion in the tire width direction of the belt layer 7. The belt reinforcing layer 8 is provided by winding a strip-shaped strip material (for example, a width of 10 [mm]) in the tire circumferential direction.

The inner liner layer 9 is the inner surface of the tire, that is, the inner peripheral surface of the carcass layer 6, and both end portions in the tire width direction reach the lower portions of the bead cores 51 of the pair of bead portions 5 and are formed in a toroidal shape in the tire circumferential direction. It is hung around and pasted. The inner liner layer 9 is for suppressing the permeation of air molecules to the outside of the tire.

In the pneumatic tire 1 described above, a protrusion 10 is provided on the shoulder 3. The protrusion 10 is provided continuously in the tire circumferential direction, and is provided on the outer side in the tire width direction from the opening of the lug groove 24 provided on the outermost side in the tire width direction of the tread portion 2. The protrusion 10 is formed to protrude outward in the tire radial direction. In addition, the protrusion 10 is the maximum of the outermost lug groove 24 in the tire width direction in the meridional section in a state in which the pneumatic tire 1 is assembled on a regular rim, filled with a regular internal pressure, and loaded with 70% of the regular load. The front end 10a is disposed on the inner side in the tire radial direction than the tread surface S of the tread portion 2 while extending outward in the tire radial direction from the groove bottom R of the groove depth. The lug groove 24 may be configured to partially bite into the inner surface of the protrusion 10 in the tire width direction.

Here, the regular rim is “standard rim” defined by JATMA, “Design Rim” defined by TRA, or “Measuring Rim” defined by ETRTO. The normal internal pressure is “maximum air pressure” defined by JATMA, the maximum value described in “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” defined by TRA, or “INFLATION PRESSURES” defined by ETRTO. The normal load is “maximum load capacity” defined by JATMA, the maximum value described in “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” defined by TRA, or “LOAD CAPACITY” defined by ETRTO.

Further, the tread surface S is a surface on which the tread surface 21 of the pneumatic tire 1 comes into contact with the road surface when the pneumatic tire 1 is assembled on a normal rim, filled with a normal internal pressure and loaded with 70% of the normal load. It is.

That is, according to the pneumatic tire 1, the protrusion 10 is located at the position of the opening on the outer side in the tire width direction of the lug groove 24, so that when the vehicle equipped with the pneumatic tire 1 is traveling, the lug groove 24 The air column resonance sound to the outside in the tire width direction is shielded to prevent emission. As a result, noise outside the vehicle can be reduced.

In the pneumatic tire 1 of this embodiment, the protrusion 10 includes a reinforcing portion 11 having a JIS-A rubber hardness higher than that of the surrounding rubber material. In the pneumatic tire 1 shown in FIGS. 1 and 2, the entire protruding portion 10 is configured as a reinforcing portion 11. The rubber material around the protrusion 10 includes the tread rubber 2A of the tread portion 2 and the side rubber 4A of the sidewall portion 4 described above. In the pneumatic tire 1 shown in FIG. 1, the end portion of the side rubber 4A on the outer side in the tire radial direction is disposed on the inner side in the tire radial direction of the end portion of the tread rubber 2A, and the reinforcing portion 11 has a tire diameter of the side rubber 4A. The reinforcing portion 11 is configured as a protruding portion 10 that is disposed on the outer end in the tire width direction of the tread rubber 2A. Further, in the pneumatic tire 1 shown in FIG. 2, the end portion of the side rubber 4A on the outer side in the tire radial direction is disposed on the outer side in the tire radial direction of the end portion of the tread rubber 2A, and the reinforcing portion 11 is a tire of the tread rubber 2A. The reinforcing portion 11 is configured as a protruding portion 10 that is disposed on the radially outer side and on the end portion of the side rubber 4A on the outer side in the tire radial direction.

Further, as shown in FIGS. 1 and 2, the reinforcing portion 11 may constitute the entire protruding portion 10, or may constitute a portion of the protruding portion 10. FIGS. 3 and 4 are enlarged views of the main part of the pneumatic tire shown in FIGS. 1 and 2 and show the protrusion 10 in an enlarged manner. 3 and 4, the reinforcing portion 11 is shown only outside the virtual profile F of the shoulder portion 3 between the tread portion 2 and the sidewall portion 4, and the outside of the virtual profile F is configured as the protrusion portion 10. It is a part to be done. A base portion where the protrusion 10 protrudes outside the virtual profile F is defined as a base end 10 b of the protrusion 10. 3 and 4 extends through the inside of the protruding portion 10 from the base end 10b of the protruding portion 10 toward the distal end 10a, and is provided partway along the protruding portion 10. As described above, the reinforcing portion 11 is provided at least at the base end 10 b of the protruding portion 10.

In addition, the protrusion part 10 shown to FIG. 3 and FIG. 4 is extended and the outer periphery is coat | covered with members other than the reinforcement part 11, and the inside is extended. In this case, the members other than the reinforcing portion 11 forming the outer periphery of the protruding portion 10 may be the same rubber material as the tread rubber 2A and the side rubber 4A. For example, as shown in FIG. 1, when the side rubber 4 A is arranged on the inner side in the tire radial direction of the tread rubber 2 A, the tread rubber 2 A becomes a member other than the reinforcing portion 11 that forms the outer periphery of the protruding portion 10. On the other hand, as shown in FIG. 2, when the side rubber 4 A is disposed on the outer side in the tire radial direction of the tread rubber 2 A, the side rubber 4 A becomes a member other than the reinforcing portion 11 that forms the outer periphery of the protruding portion 10. In addition, the reinforcement part 11 may comprise the whole base end 10b of the projection part 10, and members other than the reinforcement part 11 may extend from this base end 10b, and may comprise the front-end | tip 10a side of the projection part 10. FIG.

Incidentally, as described above, the reinforcing portion 11 is made of a member having a JIS-A rubber hardness higher than that of the tread rubber 2A and the side rubber 4A. Specifically, the member is a single rubber material, a cord, or the like. It may be composed of a rubber material including the reinforcing member, a thermoplastic elastomer, a thermoplastic resin, or the like.

As described above, the pneumatic tire 1 of the present embodiment has the lug groove 24 that opens to the outer side in the tire width direction on the outermost side in the tire width direction of the tread portion 2, and on the outer side in the tire width direction from the opening portion of the lug groove 24. The rim is assembled to the regular rim, filled with the regular internal pressure, and loaded with 70% of the regular load, extending in the tire radial direction outside the groove bottom R of the maximum groove depth of the lug groove 24 in the meridional section. And a projection 10 having a tip 10a disposed on the inner side in the tire radial direction from the tread surface S of the tread portion 2, and at least the base end 10b of the projection 10 is higher than the surrounding rubber material. A reinforcing part 11 of A rubber hardness is provided.

According to this pneumatic tire 1, the protrusion 10 has at least the base end 10b provided with the reinforcing portion 11 having a JIS-A rubber hardness higher than that of the surrounding rubber material (tread rubber 2A and side rubber 4A). The deformation of the part 10 is suppressed. As a result, the generation of noise due to the vibration of the protrusion 10 can be suppressed, and the original sound shielding effect of the protrusion 10 can be obtained, so that the effect of reducing outside noise can be ensured.

Further, in the pneumatic tire 1 of the present embodiment, as shown in FIGS. 3 and 4, the reinforcing portion 11 has a height h of 60% or more with respect to the extending height H of the protrusion 10 in the meridional section. % Or less is preferable.

As shown in FIGS. 3 and 4, the extending height H of the protruding portion 10 includes a center point Pa of the thickness at the distal end 10 a of the protruding portion 10 and a thickness at the proximal end 10 b (virtual profile F). ) Of the center straight line SL connecting the center point Pb. Further, as shown in FIGS. 3 and 4, the height h of the reinforcing portion 11 is, in the meridian section, from the central point Pb of the thickness of the base end 10b of the protrusion 10 to the central point of the thickness of the tip 11a. This is the length of the dimension reaching Pc projected onto the central straight line SL. In FIG. 3, the center point Pc of the thickness of the tip 11a of the reinforcing portion 11 exists on the center straight line SL.

According to the pneumatic tire 1, the height h of the reinforcing portion 11 is in a range of 60% or more and 100% or less with respect to the extending height H of the protruding portion 10, thereby suppressing deformation of the protruding portion 10. The effect of suppressing the vibration due to the deformation of the protrusion 10 can be remarkably obtained. When the height h of the reinforcing portion 11 is less than 60% with respect to the extending height H of the protruding portion 10, the effect of suppressing the deformation of the protruding portion 10 is reduced. In order to obtain a remarkable effect of suppressing vibration due to the deformation of the protrusion 10, the height h of the reinforcing portion 11 is preferably 70% or more with respect to the extension height H of the protrusion 10. % Or more is more preferable. That is, it is more preferable that the height h of the reinforcing portion 11 is closer to 100% with respect to the extending height H of the protruding portion 10.

Moreover, in the pneumatic tire 1 of the present embodiment, as shown in FIGS. 3 and 4, the reinforcing portion 11 has a thickness t of 50% or more and 100% or less with respect to the thickness T of the protrusion 10 in the meridional section. It is preferable that

As shown in FIGS. 3 and 4, the thickness T of the protrusion 10 and the thickness t of the reinforcing portion 11 are on a line perpendicular to the center straight line SL, which serves as a reference for the heights H and h, in the meridional section. It is the dimension. In addition, the protrusion 10 can fully obtain the original sound shielding effect by the protrusion 10 by setting the thickness T at a position where the height H is 50% to a range of 1 mm to 15 mm.

According to the pneumatic tire 1, the thickness t of the reinforcing portion 11 is in the range of 50% to 100% with respect to the thickness T of the protruding portion 10, thereby suppressing deformation of the protruding portion 10 and the protruding portion. The effect which suppresses the vibration by 10 deformation | transformation can be acquired notably. When the thickness t of the reinforcing portion 11 is less than 50% with respect to the thickness T of the protruding portion 10, the effect of suppressing the deformation of the protruding portion 10 is reduced. In order to obtain a remarkable effect of suppressing the vibration due to the deformation of the protrusion 10, the thickness t of the reinforcing portion 11 is preferably 60% or more with respect to the thickness T of the protrusion 10, and is preferably 70% or more. More preferably. That is, it is more preferable that the thickness t of the reinforcing portion 11 is closer to 100% with respect to the thickness T of the protruding portion 10.

Further, in the pneumatic tire 1 of the present embodiment, the reinforcing portion 11 is a JIS-A rubber that is 3 pt higher than the highest JIS-A rubber hardness of the rubber material (tread rubber 2A and side rubber 4A) around the protrusion 10. Hardness is preferred.

According to this pneumatic tire 1, the deformation of the protrusion 10 is suppressed by making the JIS-A rubber hardness of the reinforcing portion 11 3pt higher than the highest JIS-A rubber hardness of the tread rubber 2A or the side rubber 4A. Thus, the effect of suppressing the vibration due to the deformation of the protrusion 10 can be remarkably obtained. In order to obtain a remarkable effect of suppressing the vibration caused by the deformation of the protrusion 10, the JIS-A rubber hardness of the reinforcing part 11 is the highest JIS-A rubber of the surrounding rubber materials (tread rubber 2A and side rubber 4A). It is preferable to increase the hardness by 5 pt or more.

5 to 9 are side views of the protrusion as viewed from the inside in the tire width direction. In the pneumatic tire 1 of the present embodiment, as shown in FIGS. 5 to 9, it is preferable that the protrusion 10 has an unevenness 10c on the inner surface in the tire width direction.

5 has a plurality of circular irregularities (convex portions or concave portions) 10c formed on the inner surface in the tire width direction. Further, the protrusion 10 shown in FIG. 6 has a plurality of line irregularities (convex portions or concave portions) 10c formed in parallel in the tire circumferential direction and in the tire radial direction on the inner surface in the tire width direction. Yes. Further, the protrusion 10 shown in FIG. 7 has a plurality of line irregularities (projections or recesses) 10c arranged in parallel in the tire radial direction and in the tire circumferential direction on the inner surface in the tire width direction. Yes. Further, the protrusion 10 shown in FIG. 8 is formed on the inner surface in the tire width direction with a plurality of linear irregularities (convex portions or concave portions) 10c that are curved in the tire radial direction and arranged in parallel in the tire circumferential direction. ing. Further, the protrusion 10 shown in FIG. 9 is provided on the inner surface in the tire width direction so as to be inclined with respect to the tire radial direction and adjacent to each other on the tip 10a side and the base 10b side of the protrusion 10 are connected to each other. The unevenness | corrugation (convex part or recessed part) 10c of the done filament is formed. In addition, the form of the unevenness | corrugation 10c is not restricted to the form mentioned above, Only a convex part, only a recessed part, or a convex part and a recessed part may be mixed.

According to the pneumatic tire 1, since the unevenness 10 c is formed on the inner surface in the tire width direction of the protruding portion 10, the surface area of the inner surface in the tire width direction of the protruding portion 10 is increased. Since the sound shielding area increases, the sound shielding effect can be obtained remarkably.

Further, in the pneumatic tire 1 of the present embodiment, as shown in FIGS. 1 and 2, the protrusion 10 is assembled to the normal rim, filled with the normal internal pressure, and loaded with 70% of the normal load. In the meridional section, the distance D in the tire radial direction between the tread surface 2 of the tread portion 2 and the tip 10a is preferably 0.5 mm or more.

When the distance D in the tire radial direction between the tread surface 2 of the tread portion 2 and the tip 10a is less than 0.5 mm, when the pneumatic tire 1 is deformed when the vehicle is traveling, the frequency with which the protruding portion 10 contacts the road surface or the like. The number of protrusions 10 is likely to be deformed and increased. Accordingly, by setting the distance D in the tire radial direction between the tread surface 2 of the tread portion 2 and the tip 10a to be 0.5 mm or more, the protrusion 10 is less likely to be deformed. Can do.

Further, in the pneumatic tire 1 of the present embodiment, as shown in FIGS. 3 and 4, the protrusion 10 is assembled with a normal rim, filled with a normal internal pressure, and loaded with 70% of the normal load. The angle θ between the central straight line SL and the tire radial direction line L in the meridional section is preferably in the range of 15 ° or less on the inner side in the tire width direction and 45 ° or less on the outer side in the tire width direction.

Here, when the angle θ of the tire radial direction line L is set to 0 °, if the inclination in the tire width direction inside is minus and the inclination in the tire width direction outside is plus, the range of the angle θ is −15 ° or more. + 45 ° or less.

When the angle θ formed by the center straight line SL and the tire radial direction line L is less than −15 ° (minus the negative angle), the protrusion 10 is likely to come into contact with the tire body. May cause wear and chipping. On the other hand, when the angle θ formed between the center straight line SL and the tire radial direction line L exceeds + 45 ° (the positive angle increases), the projection 10 is moved away from the lug groove 24, and it is difficult to obtain a sound shielding effect. Become. Therefore, by setting the angle θ formed by the center straight line SL and the tire radial direction line L to be in the range of −15 ° to + 45 °, the sound shielding effect by the protrusion 10 can be remarkably obtained. In order to obtain the sound shielding effect by the protrusions 10 more remarkably, it is preferable that the angle θ formed by the center straight line SL and the tire radial direction line L is in the range of −5 ° to + 30 °.

Further, in the pneumatic tire 1 of the present embodiment, the direction inside and outside the vehicle is specified when the vehicle is mounted, and it is preferable that the protrusion 10 is formed at least on the vehicle outer side.

The designation of the inside / outside direction of the vehicle when the vehicle is mounted is not clearly shown in the figure, but is indicated by, for example, an index provided on the sidewall portion 4. And when it mounts | wears with a vehicle, the side which faces the inner side of a vehicle becomes a vehicle inner side, and the side which faces the outer side of a vehicle becomes a vehicle outer side. In addition, designation | designated of a vehicle inner side and a vehicle outer side is not restricted to the case where it mounts | wears with a vehicle. For example, when the rim is assembled, the direction of the rim with respect to the inside and outside of the vehicle is determined in the tire width direction. For this reason, when the pneumatic tire 1 is assembled with a rim, the orientation with respect to the vehicle inner side and the vehicle outer side is designated in the tire width direction.

Since the outside noise is emitted to the outside of the vehicle, according to the pneumatic tire 1, the projection 10 is formed at least on the outside of the vehicle, so that the sound can be effectively shielded. Can be reduced.

FIG. 10 is an enlarged cross-sectional view of a main part of another example of the pneumatic tire according to the present embodiment. FIG. 11 is a partial perspective view of another example of the pneumatic tire shown in FIG.

As shown in FIG. 10 and FIG. 11, the pneumatic tire 1 of another example according to the present embodiment has a protruding portion 10 'instead of the protruding portion 10 described above. The protrusion 10 ′ is provided continuously in the tire circumferential direction, and is provided on the outer side in the tire width direction from the opening of the lug groove 24 provided on the outermost side in the tire width direction of the tread portion 2. The protruding portion 10 ′ is formed to protrude outward in the tire radial direction. Further, a plurality of protrusions 10 ′ (four in this embodiment) are formed in the tire radial direction. 10 and 11, the protrusion 10 'is formed in a triangular shape in the meridional section, and a V-shaped groove is provided therebetween.

In this example, a performance test on passing noise was performed on a plurality of types of pneumatic tires having different conditions (see FIGS. 12 and 13).

In this performance test, a pneumatic tire (test tire) having a tire size of 245 / 40R18 93W was assembled to a regular rim, filled with a regular internal pressure (250 kPa), and mounted on a sedan type test vehicle having a displacement of 3000 cc.

The evaluation method of the passing noise was evaluated by the magnitude of the passing sound measured outside the vehicle according to the tire noise test method defined in ECE R117-02 (ECE Regulation No. 117 Revision 2). In this test, the test vehicle is run sufficiently before the noise measurement section, the engine is stopped before the section, and the maximum noise value dB (frequency in the range of 800 Hz to 1200 Hz) in the noise measurement section when coasting is run. Value) was measured at a plurality of speeds in which a speed range of ± 10 km / h with respect to the reference speed was divided into eight or more at almost equal intervals, and the average was defined as vehicle outside noise. The maximum noise value dB is the sound measured through the A characteristic frequency correction circuit using a stationary microphone installed at a height of 7.5 m laterally from the running center line and 1.2 m from the road surface at the midpoint in the noise measurement section. The pressure is dB (A). And based on this measurement result, the evaluation which made the conventional example the standard (0) is performed. This evaluation shows that the smaller the sound pressure dB with respect to the reference, the smaller the passing noise and the better the noise reduction performance outside the vehicle.

In FIG. 12, the conventional pneumatic tire does not have a protrusion. Moreover, although the pneumatic tire of the comparative example has the protruding portion having the shape shown in FIG. 3, it does not include the reinforcing portion. On the other hand, in FIGS. 12 and 13, the pneumatic tires of Examples 1 to 17 have the protrusions having the shape shown in FIG. It should be noted that the angle of the protrusion is negative for the inward inclination in the tire width direction and positive for the inward inclination in the tire width direction.

As shown in the test results of FIGS. 12 and 13, it can be seen that the pneumatic tires of Examples 1 to 17 have low passing noise and improved performance for reducing outside noise.

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 2 Tread part 2A Tread rubber 3 Shoulder part 4 Side wall part 4A Side rubber 10 Protrusion part 10b Base part 10a Tip 10c Concavity and convexity 11 Reinforcement part 11a Tip 24 Lug groove D Distance S Tread surface SL Center straight line H Height of protrusion part h Reinforcement part height T Protrusion part thickness t Reinforcement part thickness L Tire radial direction line R Groove bottom θ Angle

Claims

It has a lug groove that opens to the outer side in the tire width direction on the outermost side in the tire width direction of the tread part, is provided on the outer side in the tire width direction from the opening part of the lug groove, is assembled with a rim on a normal rim, and is filled with normal internal pressure In a state where 70% of the normal load is applied, the meridian cross section extends outward in the tire radial direction from the groove bottom of the maximum groove depth of the lug groove, and further forward in the tire radial direction from the tread surface of the tread portion. In a pneumatic tire provided with a protruding portion where
A pneumatic tire comprising a reinforcing portion having a JIS-A rubber hardness higher than that of a surrounding rubber material at least at a base end of the protruding portion.
2. The pneumatic tire according to claim 1, wherein the reinforcing portion has a height h of 60% or more and 100% or less with respect to an extension height H of the protrusion in the meridional section.
3. The pneumatic tire according to claim 1, wherein the reinforcing portion has a thickness t of 50% or more and 100% or less with respect to a thickness T of the protruding portion in the meridional section.
The reinforced portion has a JIS-A rubber hardness that is 3 pt or more higher than the highest JIS-A rubber hardness of the rubber material around the protrusion. Pneumatic tires.
The pneumatic tire according to any one of claims 1 to 4, wherein the protrusion has an uneven surface on an inner surface in the tire width direction.
The projecting portion is assembled with a normal rim, filled with a normal internal pressure, and loaded with 70% of the normal load. In the meridional section, the distance in the tire radial direction between the tread surface and the tip of the tread portion is 0.5 mm. The pneumatic tire according to any one of claims 1 to 5, wherein the pneumatic tire is as described above.
The protrusion is assembled with a normal rim, filled with a normal internal pressure, and loaded with 70% of the normal load. The angle formed by the central straight line and the tire radial direction line in the meridional section is 15 inward in the tire width direction. The pneumatic tire according to any one of claims 1 to 6, wherein the pneumatic tire is in a range of 45 ° or less and to the outside in the tire width direction of 45 ° or less.
The pneumatic tire according to any one of claims 1 to 7, wherein a direction inside and outside the vehicle is specified when the vehicle is mounted, and the protrusion is formed at least on the vehicle outer side.